The purpose of this study is to determine whether a relationship exists between a previously established diagnosis of endometriosis and the consecutive risk of developing a clear cell or endometrioid ovarian carcinoma. All histopathological records since 1980 with these diagnoses (endometriosis, clear cell and endometrioid ovarian carcinoma) will be reviewed. Cancer registry data will be assessed to investigate differences in survival of women with endometriosis-associated ovarian carcinomas and those ovarian carcinoma patients without previous diagnosis of endometriosis.